This section provides background information related to the present disclosure which is not necessarily prior art. This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
Existing e-jet print head designs aimed at reducing the standoff height effect on deposition volume involve a nozzle extractor ring mechanism. However, the present teachings vary from conventional designs in several ways. In some embodiments, the present teachings employ a conductive rod rather than a nozzle with an inner fluid channel, and a secondary rod/nozzle that serves as a reservoir for the printing process. In some embodiments, the present teachings employ a wetting system that releases a controlled volume of material on the surface of the conductive rod and an automated rod positioner that moves the ejection rod away from the reservoir to mitigate interference between these two components.
According to the principles of the present teachings, two major printing challenges within the electrohydrodynamic jet (e-jet) printing industry are addressed. The present teachings mitigate the nozzle clogging issues present in electrohydrodynamic jet printing with nozzles containing <10 micron openings, and decouple the relationship between printing volume and standoff height of the printing nozzle, therefore promoting consistent amounts of ink to be deposited onto the printing surface even if the printing surface is not flat.
Many inks with a low boiling point (high volatility) are used for inkjet printing; however, the application of these materials in the e-jet printing process is limited due to challenges with ink evaporating and clogging the small openings of the e-jet nozzles. Using a pin (conductive, non-hollow rod with small dimensions) rather than a nozzle removes the use of a small orifice in the printing process, therefore removing the potential for a clogging issue to occur during the printing process.
Conventional e-jet suffers from the influence of standoff height (distance between the nozzle and the substrate) on the printing process. Variations in standoff height result in non-consistent volume ejection during the printing process, which leads to inconsistent and uncontrollable printed patterns.
The present teachings limit the amount of ink that can be released from the pin at a given time through the use of a wetting system. In some embodiments, the wetting system of the present teachings delivers a consistent amount of ink to the tip of the pin. With a controlled volume of ink at the tip of the nozzle, the volume of ink deposited at each printing location will be the same and the standoff height will no longer influence the deposition volume.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.